Loop-taker for sewing machines



Dec. 13, 1949 w. M. ABRESKY 2,491,022

LOOP-TAKER FOR SEWING MACHINES Filed Jan. 4, 1945 INVENTOR Patented Dec.13, 1949 LOOP-TAKER FOR SEWING MACHINES William M. Abresky, Stratford,Conn.

Application January 4, 1945, Serial No. 571,232

1 Claim.

This invention relates to sewing machines, and more particularly toloop-takers of sewing machines, wherein a loop-seizing beak 0r hookperiodically engages the thread of the machine during the sewingoperations.

The invention is shown by way of example in connection with rotaryloop-takers of the type used in multiple-needle lock-stitch andzigzagstitch machines.

Many of the conventional machines of this type operate at high speeds,in the order of five thousand or more stitches :per minute. At thesespeeds, and in regular production work, many miles of stitches are sewnand the rotary looptakers, generally rotating at a speed double thenumber of stitches per minute, are subject to wear so that replacementof the entire looptaker assembly is required at not infrequentintervals.

Part of the wear, to which the rotary looptaker is subjected, is bearingwear and means are provided usually for minimizing this, to reduce thefrequency of replacement Of the loop-taker assembly. As a result, theuseful life of the looptakers has been extended to some degree by thismethod, and now they are replaced mostly because of the wear on thethread-engaging surfaces of the loop-seizing beak. When the beak of anew loop-taker has worn to the extent that it interferes with the sewingoperations, I have found that it is customary in sewing shops to advancethe loop-taker in a make-shift and inconvenient way by hammering orotherwise forcing the driving gear mechanism so that the press-fittedgears are shifted on their shafts. This expedient increases the usefullife of the loop-taker to an extent, but it is an undesirable method ofdoing this, and at times may result in breakage or other damage to themechanism, requiring the installation of new parts. No adjustment meansas such is provided for conveniently advancing the loop-taker tocompensate for the wear.

Moreover, at best the extension of life of the loop-taker is notconsiderable, and therefore eventually the entire loop-taker assemblyhas to be replaced with a new one, involving delay and expense. Over aperiod of time the number of replacements of the loop-taker assembliesbecomes considerable, so that the overall expense becomes significant.Also, at the time of installing a new loop-taker assembly, the forcedgears of the driving mechanism must be reset, thereby adding to thedificulty and expense of the replacement.

The above difficulties and disadvantages are obviated in a simple, noveland effective manner by the present invention, which provides forforming the initial thread-engaging portion of the loop-taker, which isusually the tip of the hook or beak, of an exceedingly hard,wear-resistant material such as cemented carbide, this being appliedpreferably as a slug being secured to the loop-taker by brazing or othersuitable means in place of the usual tip.

I have found that the cemented carbides, which are commonly employed forcutting tools, are suitable and desirable for use on the beak of aloop-taker as stated above to minimize to a considerable extent the wearcaused by the thread during high-speed sewing operations.

Heretofore the reduction of wear at the beak of a loop-taker wasaccomplished by overall hardening of the material of the loop-taker,beak, body and all. I have discovered, however, that the useful life Ofa loop-taker may be extended considerably by incorporating a cementedcarbide tip at the beak, and this may be done even though the beak isslender and elongate, as in the case of loop-takers used in sewingzigzag stitches.

For the latter type of loop-takers, the entire beak may be formed ofcarbide, whereas in the case of loop-takers having comparatively shortstocky beaks, the thread-engaging tips only may be formed. a

My invention may be applied to loop-takers at the time of theirmanufacture, or it may be applied as a replacement part inreconditioning a loop-taker after it has become worn, so that it may beused over again and may have a' life considerably extended beyond theoriginal.

Other features and advantages will hereinafter appear in connection withthe following description, claim and accompanying drawings, in which:

Figure 1 is a side elevation of a loop-taker embodying the invention,having a shape similar to those used for two and three needle sewing.

Fig. 2 is a face View of the loop-taker of Fig. 1.

Fig. 3 illustrates a modification of the invention, showing in sideelevation a loop-taker adapted for sewing zigzag, and

Fig. 4 is a face view of the loop-taker of Fig. 3.

The rotary loop-taker of the present invention, as shown in Figs. 1 and2, comprises a. shank l0 adapted to be secured to an actuating spindle(not shown) of a sewing machine in the usual manner, At one end of theshank In, a cupshaped body II is provided, comprising a circular rim orgib 12 carried by a plate [3 which at its center is secured to the shankIll. The body II has a flange portion l4 integral with a hook or beak I5having a shape adapted to seize the needle thread loop of the machine.The shank l0, body II and flange portion [4 may be formed of hardenedsteel, all parts integral with each other, as is common practice.

According to the present invention the beak l5 of the loop-taker isprovided with a tip or threadengaging portion it which is formed ofcemented carbide securely attached to the rest of the beak for thepurpose of minimizing wear resulting from continual periodic engagementat high speeds with the sewing thread.

The beak l 5 may be formed in various ways according to the invention.It the rotary looptaker is an old one that has been discarded from amachine because the beak has become worn beyond further use, theloop-taker may be reconditioned to give it a considerably extended lifeby cutting oil the worn tip of the beak, as along the line l'l' shown inthe figures. A slug of carbide, which may be of the type known asCarboloy or Kennametal may be formed to have a shape closelyapproximating the original shape of the beak before it became worn. Thisslug may then be secured to the remaining portion of the beak in anysuitable manner, that at present preferred being by brazing. If the slugis to be secured to the beak by brazing, I have found it desirable toform the slug approximately .010" oversize on each surface, to allow forfinish grinding. The surfaces tobe joined are made clean, and thebrazing may be done by use of a thin shim of brazing material such asEasy Flow. N0. 3, inserted between the two parts. Before applying heat,the joint may be covered with flux, and then a torch used to heat theparts and melt the brazing material.

If desired the brazing may be donewith the help of a fixture to hold theloop-taker and the slug in correct position. After the brazing, has beencompleted, the surfaces of the carbide slug are finish-ground so thatthey merge with, and become coextensive with the surfaces of theremainder of the beak.

I have found that the tip of a Worn beak may be removed for a distanceof one-quarter inch,

so that a similar length of carbide material may be brazed in place, toproduce a loop-taker of long useful life.

The present invention is also applicable to the initial manufacture ofrotary loop-takers. During such manufacture the body ll of the loop-'taker may be formed with the beak I5 shortened- 4 to the extent thatcarbide material is to be added at the tip. The slug of carbide may thenbe brazed in place or fastened in any other suitable manner, and thesurfaces finish-ground to the desired shape.

A modification of the invention is illustrated in Figs. 3 and 4 whereina. loop-taker adapted for use in sewing zigzag stitches is provided withan entire beak of cemented carbide. As shown in the figures, theloop-taker comprises a shank Hla and cup-shaped body Ha with rim or gibl2a all of which may be integrally formed of steel. The body Ila has aflange portion Ma from which extends a. beak l5a which is comparativelyelongate and slender. The beak I511 in its entirety may comprisecemented carbide material, this material being joined to the flangeportion l4a along the line ITa as indicated. I have found that. apractical and extremely wear-resistant loop-taker may thus be formed,with the entire beak 15a comprising carbide material, and thatsufiicient strength is provided to enable the looptaken to operatesatisfactorily for the purpose intended.

By the present invention there is thus provided a loop-taker for sewingmachines which is extremely resistant to Wear at the points where itengages the thread during th sewing operation, so that the loop-takerneed not be readjusted by makeshift or other methods, or eventuallyreplaced due to failure of the beak to properly handle the thread.

Variations and modifications may be made within the scope of thisinvention and portions of the improvements may be used without others.

I claim:

A metal. wear-resisting loop taker for sewing machines, including aloop-seizing beak having a tip of hard wear-resisting carbide brazedthereto with the thread-engaging surfaces thereof ground to providesmooth continuations of the thread-engaging. surfaces of the beak.

WJLLIAM M. ABRESKY.

REFERENCES CITED The following references are of record in the file. ofthis patent:

UNITED STATES PATENTS Number Name Date 620,729 Bertrand Mar. 7, 1899.1,431,380 Dickson Oct. 10, 1922 2,206,760 Turner Jan. '7, 1936 2,148,925Bochy Feb. 28, 1939 2,219,308 Haas Oct. 29, 1940

